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    <TITLE>package org.opengis.filter.sort</TITLE>
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    An <CITE>SortBy</CITE> indicates the ordering requested during a data query.
    
    The following is adapted from the following specifications:
    <ul>
    <li><A HREF="http://portal.opengeospatial.org/files/?artifact_id=8340">OpenGIS&reg; Filter Encoding Implementation Specification Version 1.1</a>
    <li><A HREF="http://portal.opengeospatial.org/files/?artifact_id=5929">OpenGIS&reg; Catalogue Service Implementation Specification 2.0.1</a>
    </ul>

    <P ALIGN="justify">An <CITE>SortBy</CITE> can be formed using the elements:
    {@link org.opengis.filter.expression.Add}, {@link org.opengis.filter.expression.Subtract},
    {@link org.opengis.filter.expression.Multiply}, {@link org.opengis.filter.expression.Divide},
    {@link org.opengis.filter.expression.PropertyName}, {@link org.opengis.filter.expression.Literal}
    and {@link org.opengis.filter.expression.Function}. They all belong to the substitution group
    expression which means that any of them can be used wherever an expression is called for. In addition,
    the combinaison of these elements are themselves expressions and can be used wherever an expression is
    called for.</P>

    <H3>FeatureCollections</H3>
    <P ALIGN="justify">The contents of a FeatureCollection are not defined with respect to order.</P>

    <H3>FeatureLists</H3>
    <P ALIGN="justify">A FeatureList represents an ordered collection of features, possibly using a
    siers of SortBy elements to define the intended order.</P>

    <H3>Catalog and Web Feature Server</H3>
    <P ALIGN="justify">Both the Catalog and Web Feature Server specifications all the use of SortBy
    during requests.</P>
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